1. Circle Graphs Interpretation and Design

2. In the News

3. Key Terms Title Categories Percentages Sectors Total numbers

4. Limitations

5. Creating Circle Graphs Required knowledge: -how to draw a circle -angles in a circle (central angle) -calculating percent

6. To create a circle graph: - draw a circle - use a protractor to measure and draw each central angle - label each sector with its category and its percent - colour or shade each sector - add a title for the circle graph

7. Key Ideas – Interpreting Circle Graphs A circle graph shows how each category of data compares to the whole using percents. The sum of all percents in a circle graph is 100%. Circle graphs are easier to interpret when there are a smaller number of categories and when the percent values are not too close together.

8. Key Ideas: Creating a Circle Graph The sum of central angles in a circle is 360 degrees. To create a circle graph: -Express each category as a percent of the total. -Use the decimal value of the percent to calculate the measure of the central angle (central angle = decimal value equivalent of percent X 360 degrees). -Use a protractor to measure and draw each central angle. -Add sector labels for the categories and a title to the circle graph.